Side effects overview
Side effects following the first dose
The first inoculation with NA can cause transient, dose-dependent side effects during the first 12 weeks. In most cases, the earliest that side effects might appear is on or after the 4th day but, occasionally, they may start from day 2 and might include coughing, respiratory symptoms, fatigue, diarrhoea, cramping, gas, nausea or vomiting - symptoms collectively known as "worm flu".
(After) my initial dose… I had 36 hours with symptoms identical to the worst flu I've ever had in my life except I had no fever. That is I had vomiting, diarrhea, and a strange feeling like time was drifting over my head. 
It feels SO MUCH like a normal flu. 
All the side effects experienced following inoculation are a result of the immune system responding to what it perceives to be an invading alien organism, and trying to get rid of this. The immune response involves an increase in eosinophils that usually begins in weeks 2-3 following inoculation, then rises more rapidly from week 4 and peaks at around weeks 5-8, before dropping back to normal at about 14 weeks. This progression can be seen in the following graph, which also illustrates why higher numbers of larvae produce more severe side effects.
Graphic taken from: Dose-ranging study for trials of therapeutic infection with Necator americanus in humans
Since the side effects are dose-dependent, their severity can be minimised by commencing with a small dose. For much more detail about the best approach to hookworm dosing, see the following page.
When the guidance to limit the size of doses is ignored, especially at the commencement of therapy, there is a risk of triggering very challenging side effects. Even starting with a small number of larvae can be tough for a few people.
I must say the 1st week (with 5 NA
) was hard. 
In addition to the side effects discussed on this page, the disease being treated can also flare during the first 12 weeks.
Going on 3 weeks since I stuck 5 NA
on my arm. In the last few days I’ve been feeling like crap. Headache, ringing ears, bloating, tired. All normal stuff for me but exaggerated. 
Week 8 was like hell for me, too. My arthritis was the worst it has ever been in my life. Now at week 9.5 I feel like things are slowly getting better. 
I did have a flare in neuropsychiatric symptoms (which is the main thing I am trying to treat) around week 10. It cleared up in a week and a half. 
Although the side effects and/or disease exacerbations tend to follow the graph shown above, self treaters can experience personal peaks at different times.
I usually have week 3 as my worst. 
Week 8/9 was the worst for me. 
There may also be a reappearance of old injuries and illnesses (see this section, below), but, in most cases, the side effects and exacerbations resolve between 12 and 14 weeks, eventually giving way to the emergence of benefits.
both times I experienced increased chronic fatigue and lasting low energy. It was bumming me out and lasted for weeks. Now it’s passed. I have great energy. Normal bowel movements. Asthma disappeared. Pollen allergies disappeared. Strange headaches that were chronic are gone! Sleep is great. Sexual function is even boosted. 
As well as being dose-dependent, the severity of side effects varies widely between individuals and is to some extent determined by the subject’s disease.
There is no reliable link between the presence or severity of side effects and eventual success with the therapy.
For what to expect in the days, weeks and months after first inoculating with hookworms, including all the typical side effects, see the following page.
The 'bounce' - a very enjoyable side effect!
A much more welcome phenomenon that may be experienced by some new helminth self-treaters is the so-called 'bounce', which can provide a brief period of temporary, yet sometimes profound, symptom relief accompanied by a sudden feeling of unusual wellness, and perhaps also by a strong sense of calm, focus, happiness and lightheartedness. For more details, see the following page.
Side effects following supplementary doses
Once there are mature worms living in the gut, these help to modulate the immune response to any new worms that are added. Therefore, when side effects occur following supplementary doses, these usually reduce progressively with each successive dose, and are typically absent in the long term unless overly large doses are added.
I had very sharp pain the first time. On the second, I am just getting a tightness in the same area. So quite different. 
The side effects with my first dose were pretty discouraging! They got better with the second dose, and I am glad that I kept going. 
The first dose (25 NA
) was extremely painful to the point I wanted to take anthelmintics
to terminate them. The other doses (10, 25, 25) were gradually less painful. 
I had a bad reaction of poor energy with my first and second innoculation, first one lasted quite a few weeks, second one less and now its not long at all... days if anything... 
I noticed last time I did 10 NA
and again this time I have done another 10 NA
, that my hot flushes (hot flashes) that had virtually gone, have come back for I think it was the first 8 weeks or so (on and off). 
Side effects that recur following inoculations in the longterm
There are a few individuals who continue to experience side effects after inoculations in the long term.
I still get a spike in inflammation when I take a new dose and I do the therapy for about 2 years now. It only is for a few days though and for me it’s a sign of a successful inoculation
I have Graves' and I have symptom flares from that when I inoculate. I introduced 10 more NA
on March 12th and I've had disease symptoms flaring for the past week (second week of May). I'd expect them to continue for another month or so based on previous experience. 
I feel dead tired for about 4 to 6 weeks following a hookworm inoculation
. The peak of these effects happens at the 6 to 8 week mark. It can be really challenging. 
I usually add 7 NA each time, and I always get side effects. They're not horrible horrible, but they start around week 3 and sometimes last till week 9, peaking between weeks 3 and 5. The nausea is often sporadic, usually lasts for about a week and can be really bad. It almost feels like I’m pregnant! I get lymph node pain in my arm pits and knee pain or joint aches, and a flu-like feeling throughout my body. My extremities (hands, feet and nose) get cold, I get very tired and I sleep more during this time. My heart can also skip beats and I can get breathing issues. This happens to me at every inoculation to the point where my family knows. When I begin complaining, they tell me: Oh, you just took your worms… it will go away. (Via Messenger.)
Every time I apply Hookworms
, a couple of weeks (sometimes days) later I get a red left (or right, or sometimes both) eye(s). It happens 2-3 weeks after inoculation
, without any pain or itch, and persists for a very long time. (Edited from two posts:  
I got random skin inflammations and 1 or 2 "puffy eye" each time I upped my dosage. 
My symptoms always seem to peak right at 8 weeks after a new inoculation
. Did 7 last time, and my left eye was swollen nearly shut this morning, plus lots of skin rashes and sores, and unhappy gut. And 3 days later I started 9 days of deep despair. I know it’s temporary, so I just hang on and get through it, but now I know 7 is too many. The inoculation
before this, I woke up exactly 8 weeks after inoculating, with both eyes swollen shut and the right one streaming gobs of goo.  
The author of this last comment has also reported that her response to each inoculation can be quite different, ranging from just a few symptoms to a complete melt down.  And new symptoms that appear following inoculation can last anywhere from a couple of days to 6 months. 
Side effects that persist in the longterm
In a few rare cases, a side effect may persist more or less indefinitely.
I tend to get flatulence that really never goes away... This is about the 7th or so time I have been inoculated… but I have had the flatulence the entire time. 
Side effects in detail
The chance of an anaphylactic reaction to helminthic therapy is extremely small, but it is possible, especially with large doses of hookworms. For more detail, see Helminthic therapy and anaphylaxis.
Helminth doses, including doses of NA, can occasionally produce a temporary increase in anxiety. See Temporarily increased anxiety.
But, in the longer term, helminths are likely to alleviate anxiety. See Helminthic therapy personal stories: Anxiety.
Body odour / body odor, increase in
This effect may be partly related to an improving sense of smell, which some new hookworm hosts have reported. 
One really weird thing I've been noticing pretty much since I've innoculated is I'm sweating and actually have BO. I usually don't have any BO at all!
The first weeks after my inoculation
my sweat smelled like it did in my twenties. 
Weird thing-My feet have never smelled. Like, it’s a thing. Well I’m sad to report this as an unfortunate side effect of NA
- they are no longer so pleasant 
The week I took my first dose of NA
, I had my first-ever experience with claustrophobia. I awoke in the middle of the night, feeling constrained. I got up, went outside, breathed big and deep, and the sensation passed. IIRC, it happened again the next night, but not as severely. It did not repeat itself after that. 
The constipation started a week after inoculation
and was suddenly gone on about day 20. 
See here for examples.
Depression can present temporarily following the first inoculation, and is most likely to appear in those with a pre-existing tendency to this condition. See Temporarily increased depression.
In the longer term, hosting hookworms can bring about a reduction in depression. See Reduced depression / improved mood.
Diarrhoea / diarrhea
I was having bad diarrhea every day starting around week three or four. 
One self-treater, who had a longstanding problem with diarrhoea, found that this became even worse for several months after a first dose of 15 NA.
I had science fiction level diarrhea... took a few months to decrease.
Well, I finally have decided (39 days in) that my 10 NA
are there - just a little slow on the uptake. The last couple of days the gut has become increasingly uncomfortable, with some severe pains and quite a lot of dizzy spells. 
I'm about 3.5 weeks into 20 NA
. It’s my 3rd and highest dose thus far over the last 2 years… Starting around inoculation
time, I began getting little head rushes here and there and it has been building up to full dizzy spells. 
This is particularly likely in someone with M.E./CFS, especially if they start with more than 3 NA. 
I have CFS and started with 5. This was too much as my fatigue got a lot worse for many weeks. 
The following comment was reported at 2 days by a patient with CFS/M.E. who had inoculated with 5 larvae.
Horrible fatigue today…
This was followed by the further comment at 4.5 weeks.
Too much fatigue, can't stand any more. This is simply unbearable… 
Gas / flatulence
Day 4 now, and I have enough gas to power a sail boat on a world trip. 😂 
Toxic farts!... about 1-2 weeks of strange, otherworldly smells...  
The noxious gas and runs are more common in week 3 for me. 
I think i started noticing gas, diarrhea and ab pain right around week 3. Very gassy, very odorous and painful. It lasted for 2-3 weeks.   
I had odorous and painful gas with bloating and cramps with one of the doses. Peak was between week 6-8. 
I swear my last batch of 20 NA
had me competing with an entire dairy herd for methane production. 
GERD / reflux
A few subjects have mentioned a transient post-inoculation increase in stomach acid with heartburn/reflux.
I rarely suffer gastric reflux but usually do a few days post inoculation
My mother inoculated 5HW for dust mite allergy and atopic dermatitis 2 weeks ago. At one week she started having reflux (never had before). 
I've been having nighmarish GERD symptoms since about week 2, accompanied with horrible belching. 
I inoculated with 10 HW at the end of September. I had zero issues and was thinking of doing a second round of ten right away. Then, in the beginning of November I suffered from a massive increase in stomach acid production, which brought on GERD and gastritis type symptoms, along with other GI symptoms characteristic of HW infection. It was really bad for three weeks. (Link expired)
Two cases of more severe and prolonged manifestations of GERD have been reported.
Around week 9-10 (after a first dose of 5 NA
for adult onset celiac and undifferentiated connective tissue disease) I started having extreme amount of stomach acid, 10 times worse than I had ever experienced and requiring a lot more PPI and H2 blockers to function normally. My abdominal pains also worsened. With my history of GERD, I avoided prednisone and took Claritin for 3 weeks to no avail… I held on until day 139 (week 19) when I gave up and took albendazole. Within the night of the first dose (400mg per day X three days), my stomach acid subsided and got better and better. 
I went pre-worm from having occasional heartburn every few months and sort of avoiding onions, to daily agony with diagnosed gastritis and an ulcer over a 3 month period and needing medication. It showed up around the 6-10 week mark and just got worse and worse. 
This side effect is also sometimes experienced by users of TSO.
On the evening of day 3 post inoculation
with 5 NA
(my first) i started feeling a bit of a headache as I went to bed. I woke up after sleeping about 2 hours with a searing headache and growing nausea. This lasted all night and all the next day. It was very intense and I couldn’t function all day. Around 8pm, however, the headache and nausea suddenly subsided and I was able to eat again and feel pretty normal. 
See Rashes and itching distant from the inoculation site, below.
(My alcohol intolerance) was severe (vomiting, stomach cramps) and first occurred at the 8 week point after my first innoculation of 35 NA (for skin allergies). I don't drink much anyway, but it happened 3 times over 2 weeks (at which point I avoided alcohol for the next 3 months). I re-inoculated 10 weeks ago but haven't had the problem recur. (Link expired)
Both me and my mother experienced alcohol intolerance after doses of 5 NA. We both had cramping and pain - a very strong and immediate response that I discovered as soon as I sipped at a beer 1 month in. (Via private communication.)
Inoculated with 5 NA
right on 10 weeks ago. At the 8 week mark I developed - literally overnight - quite stunning alcohol intolerance. Same bottle of wine, one night to the next, went from being fine to producing immediate (upon first mouthful) burning pain in the stomach, persisting with severe cramping over an hour, resulting in vomiting and graduating to lower gut cramps and eventually, the next day, diarrhoea. Happened once with wine, then (because I didn't join the dots together and thought it was a reaction to the wine, perhaps allergic in nature) once with a clear gin mixed with soda water about a week later. Last night (2 weeks on) I tolerated a much smaller glass/half a shot mixed with soda water, but started to feel what might have been the onset of those same symptoms so gave it up as a bad job. 
A few others have reported abdominal pain after drinking alcohol, including three bouts of almost instant burning pain below the navel at 5 weeks after inoculation with 25 NA  and two incidents of mild to severe stomach pain at 4-5 months after inoculating with 20 NA. 
As with other hookworm side effects, this experience does not usually persist indefinitely, although it has done for one individual.
After 2 years with NA
, I am still unable to tolerate alcohol. It’s not an allergy, I just process it differently. I can become quite intoxicated off of one glass of wine, and initially would remain that way for several hours. Although it no longer lasts for hours, I basically still have to pass on alcohol, but obviously NA
benefits are worth the trade off. (Edited from 3 posts.) 
For most who temporarily develop this intolerance, there is much to look forward to once the worms have settled in! See Helminthic Therapy personal stories: Alcohol intolerance.
Sensitivity to caffeine may develop, or, if present previously, may increase, during the early stages of hosting NA.
I was very sensitive to caffeine and alcohol during peak NA
side effect period. 
I took a caffeine pill yesterday (200 mg) and all my symptoms immediately came back with a vengeance. I’m at week 5 of my second dose. 
This increase in sensitivity typically subsides once the worms have matured, and previous intolerance to caffeine may improve.
has made me less sensitive to the bad effects of coffee. If I ever drank more than one cup I'd get shivers and feel drunk.😆 I don't feel amazing if I drink 3 cups now, but I'm definitely not shaky or weird anymore. 
A few medical practitioners have noticed an increased rate of chicken and duck egg intolerance appearing in patients after their first inoculation with hookworms. People who normally eat a lot of eggs without issue have noted intensified acute abdominal cramping, especially at the 6 week mark and, in some individuals, this has even persisted for several months, In one case, a patient had extremely severe reactions to egg for a whole year, experiencing incapacitating bouts of abdominal cramping that would last for several hours but then resolve on their own. This reaction did eventually subside, and, by the 2nd year post inoculation, this patient was able to resume eating eggs without any issue. This phenomenon has led some clinicians to recommend patients to avoid eggs following inoculation, especially around the 6th week, to minimize the risk of increased abdominal symptoms that are typical at that period post inoculation. The egg intolerance appears to induce or worsen abdominal cramping acutely after eating, within one hour, and then subside without other incident.
I was able to eat eggs again after 2.5 years. I don’t eat them every day as I used to, but am now ok eating them several days per week. 
Self-treaters have reported the following additional transient food intolerances following inoculation.
, I was only intolerant to dairy and gluten. With my first inoculation
) I become intolerant to rice. Now with my second inoculation
- beans and probably buckwheat... 
Prior to hookworm
I only had problems with gluten and occasionally dairy. But about 3 weeks after inoculation
(with 25 larvae
) I started reacting to what seemed like almost all foods. And at exactly 12 weeks it dropped off and now, at about 15 weeks, I'm fine with all other foods again. 
Hypersensitivity to contact lenses
I became allergic to contacts (after wearing them without issue for almost 30 years) a couple weeks after my second inoculation
. It took more than a year to resolve, but I’ve gotten used to glasses again so never really went back. 
Increased reaction to insect bites
I usually don't react much to mosquito bites at all but for a couple weeks (probably around week 7) I was getting big itchy bumps that seemed to take forever to go away. I'm at 12 and a half weeks now after my first inoculation
of five NA
and mosquitoes aren't bothering me anymore.  
At week 7, have been getting huge bumps from mosquito bites on my legs and back. Tree bites is like 5 cm in diameter, usually i dont react to this. 
Hypotension (reduced blood pressure) / lightheadedness
Several people have reported a reduction in blood pressure, e.g., as reported here.
A few have described becoming light headed.
I just inoculated (with 20 NA
) and within 5 minutes, I felt the itch! Another 10 minutes and I got light headed, I'm now lying on the couch -- head spinning. 
I’ve been lightheaded for a couple of days, especially when standing up, and I've never had that before... I'm a couple weeks in. 
I, too, have had several low blood pressure events recently. I'm 2½ weeks into hosting 25 NA
. I have gone through several phases in my life when I have gotten dizzy due to low blood pressure. 
I’m one month in with 5 NA and for two days I felt lightheaded like if I was going to faint, then it went away and came back a week later. (Via private communication.)
Infections, exacerbation of
Herpes virus reactivation
One self-treater with no history of cold sores had a serious outbreak of Herpes type 1 virus a few weeks after his first dose of 5 NA. This was diagnosed as eczema herpeticum, and the individual was hospitalised for 2 days.
Urinary tract infection (UTI) exacerbation
I'm 10 weeks post inoculation
(with 10 NA
) and my UTI and related symptoms have been through the roof for the last 5 or 6 weeks. 
In week 4 or 5 after my first inoculation
with 3NA, I did notice some incipient UTI symptoms as well as some incipient yeast infection symptoms, but these never became full blown infections. 
Once the initial side effect phase has passed, NA may alleviate UTIs. See Helminthic therapy personal stories: Urinary tract infections.
Insomnia / hypersomnia
See the following separate page section.
(Also see, Helminthic therapy and menstruation.)
My menstrual cycle has changed and I've been having acne break outs on my face and chest since shortly after my first NA
I've had lighter and shorter periods with more spotting, fewer PMS symptoms, and the acne. 
I am 12 weeks in on first dose with 3NA. I have found that during these past three months, my PMS was worsened to what it was when I was a teenager - namely, irritability (verging on blind rage!) and terrible back pain, so bad I could not stand up straight for a couple of days. 
One hookworm host felt so dizzy and nauseous at work, she couldn't drive home until it passed. (Link expired)
It lasted almost all day for a few days around week 5-6 but then as I got more towards weeks 7-9 it seemed to be 2 to 3x per day. Definitely more intense early on.
... mouth pain 3 to 4 weeks after innoculating (25 hw
). Feels kind of like I burned the roof of my mouth. 
At 6 weeks (post-inoculation
) burned like tongue feeling. Not the roof of the mouth. 
I had lingua geographica (geographic tongue
) for the first time in my life after my third dose of NA
. It disappeared in a week. No treatment needed.  
Two people have reported a consistent “needing to clear throat” feeling at around 13-16 days.  
For more detail about people's experience of aches and pains following inoculation with NA, see this Support group poll and this related thread.
I would get cramps for two days with each dose. I just laid face down with a heating pad on my gut and it helped a lot. 
For the past week, 15 min after a meal I get intense intestinal pain. This resolves after 4 - 5 hours, only to come back after another meal. The pain is not in the stomach, but in the lower abdomen. I never experienced anything like this before the inoculation
. (Reported 5 weeks after inoculating with 5 NA
I'm at week 7 and only took 8 NA
. I'm having stomach aches after almost every meal. 
The only abdominal pain I felt around week 6 was for 2 days and it was intense muscle contractions/cramping of my entire abdomen. This was different from GI
-distress associated with my IBS
, which was more localized/rumbly/gas-pain that came and went. The HT
cramping was nearly constant and felt like I was doing a painful crunch/sit-up that engaged my entire core. 
Two mornings in a row (at 6 weeks post inoculation
with 20 NA
) I have had incredible pain in my abdomen - and I can't exactly pinpoint where it is located… It lasts 30 minutes or so, but during that time it is so bad I can't even describe… The pain resembles the pain I tend to feel as a result of my very painful endometriosis… But I normally only suffer from endometriosis once per month - and certainly not at this time of the month. And certainly not 2 days in a row for 30 minutes at the same time in the morning. I can only come up with the explanation that it must be the worms… The pain is so intense I feel like jumping from a roof at that very moment. 
I had pretty extreme stomach pain at times. But my illness involves stomach pain. Now that I think back and I’m out of the woods I think it was totally worth it! 
I recall experiencing what I would describe as an occasional (not constant) definite, though mild, gnawing sensation in the middle of my belly from about six weeks following inoculation
to about five or six months post inoculation
. As I was noticing steady improvement in my severe allergy and asthma symptoms, and expected to have some abdominal symptoms with HWT, for me, the gnawing sensation was encouraging, and never a real problem. 
Joint pain may be experienced by a few, especially when this was a problem prior to inoculation.
My mother inoculated 5HW for dust mite allergy and atopic dermatitis 2 weeks ago. At one week she started having... joint pain (the kind you experience when you have flu, or a fever) and light flu-like fatigue and fever. 
I’ve been on HW
for 45 days. The first 18 days were easy. Then, on day 19, I was hit with crushing fatigue for eight days…Throughout, I'd been having some joint pain (and have been for years) but it was bearable, but around day 36 the joint pain became awful -- by far the most unpleasant side-effect of the worms I've had yet -- and I'm used to a certain level of joint pain. This is truly horrible. 
At around the 7 week stage I developed strong and scary neuropathic symptoms in my feet and hands. And joint pain especially in my fingers. 
I had painful tingling in my fingers, legs, arms and feet that I described in my journal as "almost like thousands of piranha’s nibbling under my skin." I also noted "a jumpiness that feels cellular". Along with this symptom I also had severe joint pain. Lower back, ankles, neck and one knee. The worst of all of this started around week 8 after my first ever inoculation
with 5 NA
. The symptoms finally started to taper off gradually around week 11. I am now at week 14 and all of these sensations are completely gone. 
Before taking helminths
i suffered from chronic severe neck pain... When i took my first and so far only dose of NA
, the neck pain flare up occurred now and then during the initial ten weeks, but it eventually went away. Basically its gone for good as far as i can tell.  
My 10 year old son using 5 HW
for dog dander allergies experienced neck ache for a short period on day 4 and 5 after inoculation
One female subject reported pelvic discomfort on days 23 and 24 - not so much a pain as a “menstrual feeling”, as though she was about to start a period. 
Two self-treaters have had dreams that foretold improvements in their respective conditions.
Eleven weeks and five days after my new 'old friends' moved in, I woke suddenly in the night with an extremely vivid recollection of a dream. I was in an oriental take-away (not my usual haunt, of course!) trying to decide what, if anything, I could safely eat, when I became aware of someone telling me that I could have rice, meat and vegetables… I began, very gingerly at first, to try a little chicken and, as that was OK, some rice, and then potato. That I coped with all of this without any adverse reaction was utterly amazing after so many years of overwhelming food allergy and food intolerance. 
I had another crazy dream. For some reason I am really active in these dreams. Running and jumping and crawling and things AS has made it difficult to do these past 2 years.  (This individual's dreams may have been triggered by TSO rather than NA, as he was hosting both species.)
Rashes and itching distant from the inoculation site
(For the rash at the inoculation site and the itching associated with this, see The hookworm inoculation rash.)
Several people have reported transient skin manifestations away from the inoculation site, such as mild rashes, or “weird bumpy hives”, on the neck and face, a "sunburn feeling” (in the absence of any sun exposure), tiny bumps all over the forearms (beyond the rash site), and nocturnal "itch attacks" all over the body, all of which can appear from day 3 onwards but usually resolve by the tenth week.
I got full body itch after my first dose of NA
. It did pass after a week or two. Subsequent innoculations haven't brought on the full body itch. 
One individual experienced a full body rash at about 12 days after inoculation. Describing this as being similar to contact dermatitis (small raised lumps with a tiny water blister), the individual said that he had never experienced anything like this before. 
Another subject, whose skin was very itchy and flared before commencing HT as a result of chronic urticaria and severe eczema, reported, at 14 days after an initial dose of 35 hookworms:
My skin is out of control with itching and inflammation. I look like a toad. My eyelids are swollen and I'm red everywhere on my upper body. Face, neck, arms, hands. All of the same places that are normally affected but now the hives are closer together and connecting. I just can't stop scratching.
And yet another subject got a rash across his back following a supplementary inoculation,  while someone else had a rash on her chest for several days, a few weeks into her second dose of 40 hookworms. 
Others have had similar experiences up to 10 weeks post inoculation.
After about 3 weeks, I had very dramatic skin flare ups (eczema and urticaria -- the conditions I'm treating) mild joint pain, and also tingling in my hands and wrists. 
I developed hives and rashes a week or two past the 21 day point/molt. My doctor suggested that high eosinophils
might be responsible. If I had any sensitivity high eosinophils
could cause hives in cases where it wouldn't ordinarily. 
One subject reported developing a rash on her face at around 4 weeks.
I'm always suffering rashes. Never on my cheeks though. That was a very strange one. Not itchy at all and I just knew it had to be the immune response to my new friends. 
I'm at 5.5 weeks post inoculation
and I've been getting a weird rash on my face. It almost looks like my facing is breaking out with pimples, which is weird because I've always had very clear skin with no breakouts. 
At 7 weeks after inoculation with 50 hookworms, one individual had a rash appear, literally overnight, about 2 inches above his waistline. 
And another developed a facial rash at 10 weeks, on two separate occasions after doses of 75 and 50.
… a few years ago around Fall/Winter season, I woke with an odd red patch on my face, straddling my upper lip and cheek, just on one side…Flash forward to today, I've been having this same weird redness on my face. Now it's on the other side, and my chin. I determined it's "perioral dermatitis", which is a mystery to dermatologists… So I checked my calendar in 2012 when this first happened. Lo and behold I'd done a 75 hookworm
top-off, about 10 weeks before it developed. That's exactly where I'm at in the current hookworm
cycle, so I think it's safe to say one of my side effects from NA
is perioral dermatitis. 
Other experiences include the following.
I introduced 6 NA
13 days ago. (Applied them to my leg; I still have itchy welts in the area.) Six or seven days later, I developed similar itchy welts on my arms and back. 
My hives got worse when I started HT
. Seems to be settled down now though at 2+ years. LDN
helped bridge the gap. 
I had cold hives all over my face and body when I started NA
. Prior I would get mild cold hives in winter. I still get a tiny bit on my hands or arms in very very cold weather, but when initially starting NA
it was a lot stronger. Didn't last long, maybe a few weeks or so till it fully settled. 
Reactivation of sites of old bug bites and injections
Sites where the skin has previously been punctured by 'alien' organisms other than helminths, or where 'alien' material has been introduced, for example via injections, can flare unexpectedly following a helminth inoculation, even years after the introduction of helminths.
My old leech bites often wake up, swell & itch, shortly after inoculating with NA
I had (the site of) an old TB test pop up today. I don't get bug bit, ever, and I was still in my long sleeve nightgown anyway. And the TB tests are so distinctive: location, size, etc. 
I have been using hookworms
for about 5 years now and one constant is the return of old bites when eosinophils
are on the march. Usually about two weeks after inoculation
, all my old inoculation
sites will act up and get itchy. I'll get these little mosquito bite-like spots on finger and on top of toes, that itch like hell. It's like the skin "remembers" old inflammation when new NA
are getting settled. 
Recapitulation of old injuries, illnesses
A remarkable side effect phenomenon that can appear following helminth inoculation is a "strange, mysterious and magical" reappearance (recurrence, reoccurance, repeat, repetition) of symptoms from old injuries and illnesses.
This was reported by someone who inoculated with TSO a few weeks after a bout of pneumonia:
I took my very first dose of TSO
three hours ago (for Hashimoto's and psoriatic arthritis) and my lungs are killing me. Out of nowhere. Really bad pain, almost burning sensation. 
After taking her fifth fortnightly dose of 30 HDC, one self-treater reported experiencing night terrors for almost 2 weeks, before returning to “sleeping great” again.
I've started getting night terrors again! I haven't had multiple night terrors in years ever since I discovered magnesium 7-8 years ago. It's like a deep wound that healed and left a scar.  
Someone who followed two doses of 35 NA with a dose of 45, reported that this larger dose caused a reappearance of pain from past injuries.
... the finger I broke last year is killing me, my TMJ is flaring, my knee is all screwy (high school thing), another finger someone hit with a cymbal in high school hurts, and the wrist I broke 28 freaking years ago is acting up. 
Other self-treaters using NA have had similar experiences.
My first inoculation
(5NA) I ended up with weird symptoms I hadn't experienced for YEARS. Full blown reactions. 
I had "brain zaps"
briefly this morning, 32 days into inoculation
with 3NA. These are a common side effect of SSRI (antidepressant) withdrawal that I used to get when I lowered my dose or forgot to take a pill that day. It is a very distinctive feeling! (I’ve been off SSRIs for about a decade.) 
The first and second time I dosed with NA
, I got scared by some disease symptoms I hadn't seen for maybe 10 years. They dissipated after 12 weeks. Now, on my 3rd dose, I'm not having symptoms from 10 years ago but I'm having symptoms I used to have as a child (from 25-30 years ago). 
... then this morning I started having back spasms - real brief intense spasms that hunch me over, knock my breath out, and then are gone. I've had these super randomly in the past (like 3 spasms a year), but I just had 4 within 20 minutes this morning. 
One week after my 2nd innocualation of 5 NA
, I'm having a return of old pains symptoms. Yesterday, my leg was killing me! Had problems walking....then I remembered, oh yeah....I fell when walking the dog back in March, and bruised the bone. Still have a small bump. Today my jaw is aching! Oh no....I must have cracked "another" molar. But no....in the same spot? It's just an old symptom. Having a cracked molar (hidden by a filling, not visible by xrays) for 3 or 4 months was agony. This worm journey is so interesting! 
I've been on HT
for 2+ years, so maybe 9 doses (of NA
). This last time, I felt a heavy, aching soreness all up and down my right arm, and a pain near my elbow. I became seriously alarmed that I might be developing some symptoms of MS
or Parkinson's or something, because it felt like a strain to lift my arm. Then I remembered breaking my right arm at age 9 after a fall from a fast-moving horse. So strange and mysterious and magical to revisit these cellular body memories through the helminth experience. It went away after a couple of days... 
I developed pemphigoid of pregnancy 27 years ago, resolved with treatment. I developed pemphigoid on my hands 3 years ago, resolved with treatment. Now (after inoculating with NA
) I have it again on my face. 
When I was younger… my left ribcage locked up and breathing/moving hurt really bad. (This precordial catch syndrome
) would always pass eventually. As my PANS got a bit better as I grew up, these incidents essentially disappeared. After inoculating with 3NA three weeks ago, I have had several "lock-ups" of my left heart area that hurt when I breathe and move but go away in a few minutes, like when I was a kid. 
I've started getting night terrors again! I haven't had multiple night terrors in years ever since I discovered magnesium 7-8 years ago. It's like a deep wound that healed and left a scar.  
Someone else who experienced this phenomenon reported a recapitulation of the pain from all the injuries, and the symptoms of all the diseases that he had ever had, including nerve pain from an auto accident 10 years earlier and an Achilles tendon injury at the age of 8. These all began to appear within a week of his first inoculation with NA and lasted around a month, causing pain in seemingly every part of his body.
Like other inoculation side effects, these mysterious reappearances of old illnesses and injuries don't last very long, and are usually gone within 12 weeks, although it is also possible to experience this phenomenon after supplementary doses.
Wow these things are mysterious! Each successive dose, I seem to go though later periods of my illness. I’m at the most recent one: severe and long lasting reactions to trace gluten. 
Sense of smell, enhancement of
This "side effect" is sometimes evident from around 5 or 6 weeks post inoculation.
My latest symptom — at almost six weeks — is heightened sense of smell. I can literally smell the chlorine in tap water, which I don’t drink BTW, and subtle scents in clothes, towels, cloth napkins, etc. I can also taste the subtle differences in water. The spring water at my office tastes different than the filtered water I use at home. If water sits in a glass for any length of time, I can tell exactly which scents it has absorbed. At the moment, I could tell you what my downstairs neighbor is cooking for dinner! It’s incredible. Before, my sense of smell was pretty horrible, honestly. I couldn’t smell much of anything. Right now, I could get a job as a wine taster — if I could get rid of my histamine intolerance! 
A couple of days ago I went to an excercise class with a small group of ladies and I could smell the burning oils and the yoga mats and the blankets and the tea they were drinking. It has been decades since I could smell like that (I can’t remember the last time) and the only thing that I’ve done differently is start hosting (NA
) about 5 weeks ago so I guess it may be the worms. 
Shortness of breath / air hunger
Shortness of breath has been reported occasionally following the first dose of NA.
I had my first round of hookworms
nearly 3 weeks ago. In the last week I have been having sharp chest pain, shortness of breath and bad depression which I never ever suffer from. 
I am in the middle of week 6 with 2 NA
. In the past week I've had two big (for me) allergy attacks or possibly mild asthma episodes. I have had this before the worms and it lasted about 10 days, including 2 trips to urgent care and 1 trip to the ER, (where) they gave me nitroglycerin which opened up my breathing and fixed the problem. I also have a minor version of breathing issues/chest tightness at night sometimes, and just sit up in bed for an hour or so and it passes. Benadryl helped last night. 
(NB. This individual was subsequently diagnosed as having MCAS
, and also likely responding to environmental mold exposure, either of which may have been involved in the respiratory problems she described.)
This side effect has been reported more frequently by hookworm hosts following their second inoculation.
I’m at about week 8 or 9 of my 2nd inoculation
. I took 15 NA
and didn't have any symptoms or side effects. All of a sudden in the last 3 days, I have experienced shortness of breath randomly throughout the day, like I can't get enough oxygen or something isn't converting correctly. I can breathe deeply but my body isn't satiated with what I'm bringing in. I don't have other symptoms (and) some parts of the day feel fine. 
I am in week 4-5 of my second dose of NA
and I have been experiencing the same thing over the last few days. It feels like ‘air hunger’ even though I seem to be breathing fine... I’ve had about 6-7 incidences of it over the past 6 days. I did have some occasional symptoms like that many years ago so also wondered if it was the ‘ return of past symptoms’ I have read about.
I had my second inoculation
3-4 weeks ago. No noticeable symptoms, but when I lie in bed at night and sometimes in the morning I can't get a full breath into my lungs.  
This happened to me about 8 weeks into my second inoculation
Not sure what to make of this. Have not experienced it until now. Most recent worms were about 3 months ago. Am experiencing the shortness of breath, as you describe it, but I have been Dx’d with two different tick borne diseases. 
Although helminthic therapy can improve SIBO in the longer term,  there has been one case where each new dose of NA has produced a temporary SIBO flare.
I may be a special case, as for me NA
always trigger a bout of SIBO. I usually have to do a fully ketogenic diet for a few weeks, then it settles down. 
(Also see 
Some self-treaters have reported temporary insomnia, while a few others have experienced hypersomnia. For more details, see Helminthic therapy and sleep.
I am into the 2nd week of my second inoculation
again). Have been feeling insanely thirsty all day. And then I looked at my notes from last time and I had the exact same thing for a week back then. 
I received a dose of 35 HW
about 3 weeks ago and last night I awoke gasping for air because my throat had closed up. It was a harrowing experience that lasted about a minute as I was unable to breathe. 
Exactly 5 days post inoculation
(with 25 NA
), I awoke in the middle of the night thinking someone was choking me. My throat was burning and closing up fast, causing my breath to rasp in my chest. 
My throat closed while eating several times (5 weeks in) after different innoculations of around 25. The first time it was quite alarming - I thought I was having an unprecedented allergic reaction. It resolves itself in a week or two, and does not happen every time I get more worms. I have been dosing for 3 years. 
Goddamn my throat closed up this morning, didn't expect that on 5 worms (NA) and not 70 days in! I've never experienced anything like it before. Luckily it only lasted a few seconds.
See: Helminthic therapy and tinnitus.
I've noticed I get twitching when my inflammation is reducing from the helminths
). I also had mad eye twitching when I did a course of FMT
, which leads me to believe it's related to the gut. The twitching is all over... sometimes rather severe to the point I can see my arm muscle moving. 
I get a few facial twitches in the first days after my (NA
) inoculations - only few twitches, then they disappear.  
I also get twitching on eyelids and more premature ventricular contractions after inoculating (with NA
). Weird neurological symptoms in general, but they are always mild and self-limiting. 
One hookworm host has reported that she gets twitches and ticks when she's in need of a new dose of NA. Once she has added a fresh dose, they go away immediately. 
Treating the side effects
If necessary, inoculation side effects can be quelled completely by taking prednisone/prednisolone. Those who are already taking 5 mg, or more, of this drug per day for a preexisting condition will usually not notice any inoculation side effects, to the extent that they may be convinced the inoculation was unsuccessful.
… we've found that a half-pill (5 or 10 mg?) of Prednisone per day is enough to kill any of those symptoms from dosing. 
I was having bad diarrhea every day from worm flu
starting around week three or four. 5mg of prednisone per day helped a lot (I'm 135 pounds). I am in week 7 now and stopped taking prednisone a few days ago (tapered off even though idk if you need to with 5mg) and feel really good. 
5-10 mg/day completely alleviated my GI
symptoms after my first inoculation
... Generally, I prefer non-pharma approaches to managing my health but was really thankful for prednisone mitigate the side effects of my first dose of NA
. It made the difference between whether or not I could get off of the couch and function throughout the day. 
(This quote includes additional details from an expired link.)
A short course of prednisone immediately following inoculation can be particularly helpful for anyone with an intestinal stricture. The drug will obviate the possibility of localised inflammation making a stricture worse. Prednisone may also be appropriate if diarrhoea or fatigue persist for more than a few days, and it could be continued for a week, with a doctor's approval, followed by a taper agreed by the doctor.
Anyone who is worried about inoculation side effects could ask their doctor for a prescription for prednisone and keep this to hand for use in suppressing the side effects if these were to become troublesome. As it should only be needed for a short time, there would be no long term adverse consequences of taking this drug.
Other steroid preparations
All the side effects are related to inflammation, so anything that reduces inflammation could potentially help.
I decided to try taking hydrocortisone with my NA
this time, to avoid the usual loose bowels in the first week. I took 8mg on day 2 then quickly tapered to 4, 3, 2mg over the next 3 days. Magic. No gut issues at all. 
Even the small amount of immunosuppression provided by a steroid nasal spray can be useful for this purpose.
I am on week 4 of 3NA and seeing some side effects. Flonase
(the sensitive kind), which I take in the spring for allergies, seems to be helping a bit. 
The side effect mechanism is very similar to allergies, so antihistamines can help and many self-treaters have reported good results with this type of drug.
Allergy medication helped me more than anything else because it calmed down my reaction. 
Taking daily Claritin seemed to all but eliminate the side effects of my last dose of 5NA. 
(antihistamine which, in the US, contains diphenhydramine) has helped a lot and keeps the (stomach) pain away for the most part. I take it several times a day. 
However, only worm-safe antihistamines should be used, and these are listed in the Human helminth care manual.
In addition to using the H1-antihistamines such as fexofenadine and diphenhydramine, there have been reports that H2-antihistamines such as ranitidine can also help   .
Vitamin D3 has also proved to be effective for this purpose. The blogger who made the first of the following comments used Orthomolecular Products Vitamin D3 50,000 IU - 15 Capsule Blister Pack.
I took one pill (50,000IU vitamin D3) last Saturday and by Sunday night the nearly constant cramping had ceased! 
Without vitamin D, I get only side effects from HW
. With vitamin D I get more benefits than side effects... I just take one dose about 60k IU every 2 weeks. 
Vitamin D is helpful for side effects. I take 50,000 IU once or twice a week when I’m feeling NA
side effects. 
A microdose of TSO
Retreated with NA
3 days ago. I took a small dose of TSO
(83 ova - 0.5ml from a bottle of 2,500) beforehand. So far it does seem to have helped. Normally the day after treating with NA
I get a strong worm flu
and feel poorly for 2-3 days. The day after treating with the NA
combo, I felt “normal." 
Low-dose naltrexone (LDN)
Low-dose naltrexone (LDN) looks promising as another means of offsetting symptoms during this side-effect phase, and is fully compatible with helminthic therapy.
CBD oil (50-100mg daily) has been reported to help reduce hookworm side effects. 
For a list of homeopathic remedies that have been used successfully to treat itching, nausea, gas, diarrhoea, exhaustion, cough and sore throat, see Homeopathic remedies used to relieve side effects following the introduction of NA.
Diarrhoea usually responds well to a standard diarrhoea relief preparation such as loperamide.
In theory, ibuprofen should work well, as it is an anti-inflammatory but, in practice, it may make things worse. Like Naprosen and other NSAIDs, ibuprofen is notorious for being hard on the stomach and gut. Paracetamol (acetaminophen) might be better.
The Lactobacillus plantarum 299v strain has been reported to help ease gastrointestinal side effects. 
In cases of severe side effects caused by inoculating with too many larvae, it may be necessary to terminate the hookworm infection and start over with a smaller number of larvae, or at least to cull part of the colony. See Reducing the size of a hookworm colony.
NB. None of the above is medical advice, and drugs like prednisone are prescription-only medications that should only be used with the guidance of a doctor. Please see the Disclaimer page.